A virtual network card in a VPC, bound to a specific Availability Zone.
Attributes:
- Primary private IPv4 (mandatory).
- Optional secondary IPv4 addresses.
- One Elastic IP per private IPv4.
- One public IPv4.
- One or more security groups.
- MAC address.
Key facts:
- Can be created independently of EC2 instances.
- Can be attached/detached on the fly to/from instances (useful for failover or maintenance).